1. Field of the Invention
The present invention is related with an information recording method and apparatus for adding and recording new record information subsequent to old record information recorded previously on a recordable information record medium, such as a high-density optical disc and the like, represented by DVD-R (DVD-Recordable) on which the information can be recorded only once.
2. Description of the Related Art
Generally, in the recordable information record medium on which the information can be recorded only once, when it is tried to later overwrite the new record information to an area on which the old record information has once been recorded, both the old record information and the new record information may be broken.
In the information recording method and apparatus for adding and recording the new record information to this kind of the recordable information record medium, when recording the new record information subsequent to the old record information, a linking area (or a boundary area) corresponding to an information amount of a single error correction unit, such as an ECC (Error Correcting Code) block and the like according to the error correcting system used therein, was conventionally provided at the linking or boundary portion of the old record information and the new record information. In the linking area, a meaningless dummy information or a predetermined RF (Radio Frequency) signal is recorded at a last portion of the old record information or a first portion of the new record information, and then the new record information is recorded thereon.
The reason why this linking portion is provided is as follows. If the linking portion is not provided, at the time of consecutively reproducing the new record information, recorded later, as well as the old record information, the RF signal may be discontinuous at the boundary of the record area of the old record information and the record area of the new record information, thereby resulting in an unstable focus servo or tracking servo control.
The reasons why the linking portion is provided for the data capacity corresponding to one ECC block is and why the meaningless dummy information or the like is recorded therein are explained below. In the conventional error correcting process, the error correction is performed by each error correction unit. If the new record information is recorded from the middle of the error correction unit, the appropriate error correction can not be performed for a head portion of the new record information, at the time of consecutively reproducing the old record information and the new record information later. Thus, the appropriately continuous reproduction can not be performed. In this regard, if the meaningless dummy information or the predetermined RF signal is recorded for one ECC block within the linking area as mentioned above, it is possible to reproduce the old record information and the new record information continuously by skipping the linking area and reproduce the new record information from an ECC block next to the linking portion, even though the overlapped portion of the old record information and the new record information in the linking portion is broken.
Further, another reason why the linking area is provided is as follows. If the new record information is recorded to follow the old record information without providing the linking area, both of the old record information and the new record information may be broken at the overlapped portion of them. In that case, if the information broken portion exceeds a single error correction unit, it is impossible to recover the broken record information. For the reasons described above, the linking area is provided at the linking or boundary portion of the old record data and the new record data.
However, the conventional error correction unit has relatively large capacity, for example, approximately 32 K bytes, and this area is entirely filled with meaningless information having no relation with the recorded information. Therefore, there is a problem that it results in an extremely ineffective use of the high-density disk or the like, which needs to record a large amount of information.
The present invention is proposed from the viewpoint of the above mentioned problems. It is therefore an object of the present invention to provide an information recording method and apparatus, which can add and record new record information with effectively utilizing a record area on an information record medium and accurately perform a consecutive and successive reproduction of old record information and new record information.
According to one aspect of the present invention, there is provided an information recording method including the steps of: applying a predetermined processing to record information divided into error correction units and generating processed record information including a plurality of record units; recording the processed record information on an information record medium; and recording, after the recording of the processed record information, predetermined dummy information for an information amount corresponding to the plurality of record units, on the information record medium, subsequent to the processed record information recorded.
In accordance with the method thus designed, a predetermined processing is applied to record information to generate processed record information. Then, the processed record information is recorded on the information record medium, and dummy information is recorded for the information amount of plural record units, subsequent to the processed record information thus recorded. Therefore, in a case of consecutively reproducing the processed record information, by replacing the reproduced dummy information with pre-set data, it is possible to perform the consecutive reproduction while carrying out the error correction within a range of an error correction capability.
The method may further include the step of overwriting dummy information including the steps of: detecting a head position of an old dummy information previously recorded on the information record medium; and recording new dummy information on the information record medium, based on the detected head position, such that a total information amount of the old dummy information after the recording of the new dummy information and the new dummy information recorded is no more than an information amount of one error correction unit.
In accordance with the method thus designed, a head position of an old dummy information previously recorded on the information record medium is detected. Then, new dummy information is recorded on the information record medium, based on the detected head position, such that a total information amount of the old dummy information after the recording of the new dummy information and the new dummy information recorded is no more than an information amount of one error correction unit.
Further, the processed record information recording step may further include the step of recording new record information on the information recording medium from a position subsequent to the new dummy information recorded. Still further, the dummy information recording step may record the new dummy information over a part of the old dummy information previously recorded.
Thus, the new record information is added and recorded subsequent to dummy information whose content is known in advance. As a result, in a case of consecutively reproducing old record information recorded prior to the old dummy information and the new record information, it is possible to perform the consecutive reproduction while carrying out the error correction within the range of the error correction capability. Since the total information amount of the old dummy information and the new dummy information is no more than that of one error correction unit, within the linking portion of the old record information and the new record information, it is possible to make an area used for recording the record information larger, as compared with the case of providing a linking portion corresponding to one error correction unit. In addition, since the recording area of the old and new dummy information, which may likely be broken due to the overwriting, is smaller than a single error correction unit, the error correction of the neighboring record information is not disturbed. As a result, it is possible to accurately perform the consecutive reproduction.
Alternatively, the processed record information recording step may include the steps of: detecting a head position of the dummy information previously recorded on the information record medium; determining a recording start position from which new record information is recorded on the basis of the detected head position of the dummy information and an information amount in a single error correction block which is a minimum information unit of error correction; calculating an information removal amount corresponding to an information capacity in an area from the head position to the recording start position; removing the record information corresponding to the calculated removal amount from a head of the record information so as to produce an actual record information; and recording the actual record information from the recording start position onto the information recording medium.
In accordance with the method thus designed, an information amount of the new record information at the head portion, which may likely be broken at the time of recording the new record information, is no more than the correction block that is the minimum unit for an error correcting process. Accordingly, it is possible to minimize the deterioration of the error correction performance in consecutively reproducing the old record information and the new record information. As a result, even if there is dust or the like on the information record medium at the time of reproduction, it is possible to achieve reliable error correction performance. Moreover, there is apparently no existence of the linking portion between the old record information and the new record information because the dummy information portion recorded previously and the new record information, which is likely be broken, are restorable by the error correction. As a result, it is possible to make the area used for recording the record information larger, as compared with the case of providing the linking portion corresponding to the entire error correction unit.
Also, the recording start position determining step may determine the recording start position within an area where the dummy information is previously recorded. By this, new record information is recorded subsequent to the dummy information having a content that is known in advance. As a result, it is possible to make the deterioration of the error correction performance smaller, when consecutively reproducing the old record information and the new record information.
According to another aspect of the present invention, there is provided an information recording apparatus including: a unit for applying a predetermined processing to record information divided into error correction units and generating processed record information including a plurality of record units; a unit for recording the processed record information on an information record medium; and a unit for recording, after the recording of the processed record information, predetermined dummy information of an information amount corresponding for the plurality of record units, on the information record medium, subsequent to the processed record information recorded.
The apparatus may further include a unit means for overwriting dummy information including: a unit for detecting a head position of an old dummy information previously recorded on the information record medium; and a unit for recording new dummy information on the information record medium, based on the detected head position, such that a total information amount of the old dummy information after the recording of the new dummy information and the new dummy information recorded is no more than an information amount of one error correction unit.
Still further, the processed record information recording unit may further include a unit for recording new record information on the information recording medium from a position subsequent to the new dummy information recorded. Also, the dummy information recording unit may record the new dummy information over a part of the old dummy information previously recorded.
Alternatively, the apparatus may be so configured that the processed record information recording unit includes: a unit for detecting a head position of the dummy information previously recorded on the information record medium; a unit for determining a recording start position from which the new record information is recorded on the basis of the detected head position of the dummy information; a unit for calculating an information removal amount corresponding to an information capacity in an area from the head position to the recording start position; a unit for removing the record information corresponding to the calculated removal amount from a head of the record information to produce an actual record information; and a unit for recording the actual record information from the recording start position onto the information recording medium. Further, the recording start position determining unit may determine the recording start position within an area where the dummy information is previously recorded.
The nature, utility, and further features of this invention will be more clearly apparent from the following detailed description with respect to preferred embodiments of the invention when read in conjunction with the accompanying drawings briefly described below.